1. Field of the Invention
This invention relates to vehicle automatic and semiautomatic power transmission systems providing a pluraiity of gear reduction ratios, such as automatic mechanical transmissions (i.e. "AMTs"), and, to control systems and methods therefor. In particular, the present invention relates to control systems and methods for automatic mechanical transmission systems wherein gear selection and shift decisions are made and/or executed based upon measured and/or calculated parameters such as vehicle or transmission output shaft speed, transmissoon input shaft speed, engine speed, throttle position, rate of change of throttle position, rate of change of vehicle and/or engine speed and the like. More particularly, the present invention relates to a method for controlling an AMT system after completion of a transmission gear change operation including controlling the rate and manner of returning control of the fuel supply to the engine to the vehicle operator.
2. Description of the Prior Art
The use of automatic transmissions of both the automatic mechanical type utilizing positive clutches and of the planetary gear type utilizing frictional clutches is well known in the prior art as are control systems therefor. Electronic control systems utilizing discrete logic circuits and/or software controlled microprocessors for automatic transmissions wherein gear selection and shift decisions are made based upon certain measured and/or calculated parameters such as vehicle speed (or transmission output shaft seeed), transmission input shaft speed, engine speed, rate of change of vehicle speed, rate of change of engine speed, throttle position, rate of change of throttle position, full depression of the throttle (i.e. "kickdown"), actuation of the braking mechanism, currently engaged gear ratio, and the like are nnown in the prior art. Examples of such automatic/semiautomatic transmission control systems for vehicles may be seen by reference to U.S. Pat. Nos. 4,361,060; 4,551,802; 4,527,447; 4,493,228; 4,425,620; 4,463,427; 4,081,065; 4,073,203; 4,253,348; 4,038,889; 4,226,295; 3,776,048, 4,208,929; 4,039,061; 3,974,720; 3,478,851 and 3,942,393, the disclosures of which are all hereby incorporated by reference.
Automatic control systems/subsystems for automatically controlling the engagement and disengagement of AMT system vehicle master clutches are known in the prior art as may be seen by reference to U.S. Pat. Nos. 4,081,065; 4,401,200; 4,413,714; 4,432,445, 4,509,625 and 4,576,263, the disclosures of all of which are hereby incorporated by reference. One control system for adjusting fuel control in view of throttle setting is, by way of example only, illustrated in U.S. Pat. No. 4,493,228, the disclosure of which is hereby incorporated by reference.
While the above referenced automatic/semi-automatic transmission control systems are effective to control the supply of fuel to the engine under most coniitions, under certain conditions, if fuel is allowed to be supplied to the engine in accordance with throttle pedal setting and/or if allowing operator control of the supply of fuel to the engine after a shift is not accomplished as rapidly as possible without causing driveline jolts, the control of the engine may be objectionably sluggish and/or may not provide acceptably smooth vehicle operation.